The rule is explicit, and this was called correctly. This was clear interference, and impact on the play doesn't (and shouldn't) matter.
It does feel a little overly punitive. The counter-argument to that is that, the WS did 2 separate, unrelated things wrong on this play, so it makes sense to penalize them for both.
Maybe the rule should be, if you interfere and infield fly is called, the ball is dead and runners have to go back to their previous bag? But I get why the rule exists too, you don't want to allow any reason to incentivize interfering with the fielder.